The present invention relates to the field of lead frames and methods. More particularly, the present invention relates to lead frames and methods of especial utility in the handling of a plurality of electronic parts of small physical dimensions.
In the manufacture of miniature electronic devices, it is common practice to individually bond a plurality of circuit die elements or other devices to respective bonding pads attached to strip like lead frames. Lead frames of this type facilitate the pick and place positioning and bonding of the individual circuit elements to the bonding pad during this operation. Ultimately, these individual circuit elements with the bonding pad must be separated from the lead frame by removal of the tag securing them to the frame. Generally this must be done prior to testing, lead bending, marking or other subsequent operations.
However, these parts are inherently difficult to handle individually due to their small size, and overall, the physical dimensions of such circuit elements are continually decreasing as technology progresses. Moreover, upon removal from the lead frame, the proper orientation of each element becomes lost and they must be reoriented with the expenditure of even greater operator time and effort.
To solve the problem of individually retaining the circuit elements upon removal of the tag securing them to the lead frame, there has previously been proposed the conjunctive use of a paper or plastic tape having individual pockets to retain the removed elements. This tape, advanced 90 degrees to the longitudinal axis of the lead frame, allows the individual elements to drop in a random orientation into a retaining pocket upon its removal from the lead frame. However, this method is expensive to implement in terms of both tape and related equipment, does not retain a uniform orientation of the part and adds an additional handling step prior to performing tests, marking or lead bending operations.
It is therefore an object of the present invention to provide an improved lead frame and method.
It is further an object of the present invention to provide an improved lead frame and method which is inexpensive to implement using readily available materials.
It is still further an object of the present invention to provide an improved lead frame and method in which the orientation and position of the individual elements is maintained.
It is still further an object of the present invention to provide an improved lead frame and method which does not require an additional handling step.
It is still further an object of the present invention to provide an improved lead frame and method which allows the individual elements to be handled as a unit through test, marking and lead bending operations.